That's all.
Janek Sunber. A really complex and well written imperial character who didn’t defect to the rebellion despite the fact that his childhood friend (Luke) tried to convince him otherwise. Canon could really use an onscreen storyline of an imperial that doesn’t defect and is relatable as a character. He had a sense of honor, repeatedly struggled with the reality of Luke and Bigg’s decisions, and he mourned the deaths of his fellow soldiers. His conflicted feelings regarding Luke lead to a very emotional confrontation between the two of them.
Kir Kanos would also be a very great character to do an onscreen storyline on since we don’t have a lot of onscreen material with Palpatine’s Royal Guards.
I also wouldn’t mind seeing Winter Celchu get more spotlight. She’s a highly underrated character even by legends standards. She’s Leia’s adoptive sister and her confidant in many ways. She’s extremely tactical and very great at undercover work. She’s a master of concealing her emotions for the good of the mission. She was also a very patient caregiver to the the solo children.
Luuke Skywalker... and retcon him into TLJ Luke. The real Luke will be with these other characters, having actually gone off with his family to rebuild the true Jedi Order hidden from the rest of the galaxy. Let's say they're on the Force Priestesses world, which is why they're truly out of contact...
Mara Jade Skywalker
The Twins Jaina and Jacen plus their little brother Anakin, but now shifted to Luke and Mara Jade's kids. Hey, If Ben is now a Solo which was the son of Luke and Mara in Legends, then the Solo kids can now become Luke and Mara's kids.
Legends Rogue + Wraith Squadrons and family members (Wedge/Iella, Tycho/Winter, Corran/Mirax, Wes, Hobbie, etc)
Other key Jedi of Luke's New Jedi Order like: Kam/Tionne Solasar, Cilghal, Kyp Durron, Tenel Ka Djo, Tahiri Veila, Lowbacca, Zekk, Ganner, Kyle Katarn, Jaden Korr, and Saba Sebatyne. Heck maybe Quinlan Vos/Khaleen Hentz and their Son too, plus some Canon only characters like Cal Kestes/Merrin or Erza/Sabine (just not Jacen Syndula... don't need the easter egg to Jacen Solo/Skywalker when we basically got the slightly altered Canon version here)
I agree with LordRyus
Definitely Janek as my American Graffiti post can attest.
Xanatos, Ferus Olin and Jax Pavan.
I'd love for Galen Marek (and possibly his clone/clones) to be canon too but only if they get creative with his appearance in the timeline instead of nerfing him totally. Like freezing him inside the same type of tech that kept the Clone medic Kix frozen so that he wakes up post Original Trilogy (Maybe even post-Sequel Trilogy). Give him some other Sith threats to fight against.
What do you think?